Priority to German Patent Application No. 101 02 808.3, which is incorporated-by-reference herein, is hereby claimed.
The present invention relates to an automatically closing surface element at the periphery of cylinders, for example, at the periphery of copy-carrying folding cylinders in folding apparatuses.
U.S. Pat. No. 5,429,578 relates to a folding apparatus for a rotary printing press. In a folding apparatus for cutting and folding continuous material webs from which folded copies are cut off are included a cutting cylinder and a transfer cylinder cooperating therewith. The transfer cylinder is driven and, moreover, cooperates with a folding jaw cylinder. The transfer cylinder includes an outer surface at which a number of sets of impaling pins and folding blades are accommodated which push the copies that are cut off from the continuous material web into folding jaws. The transfer cylinder is designed in such a manner that the rotational position between the sets of impaling pins and the folding blades can be varied. In the region of the outer surface of the transfer cylinder, moreover, a set of closing surfaces are accommodated on each side of a folding blade and of a set of impaling pins, the closing surfaces moving relative to each other in such a manner that they overlap one another, thus forming a virtually continuously closed outer lateral cylinder surface, independently of the rotational position of the sets of impaling pins and of the folding blades on the copy-carrying cylinder with respect to each other.
U.S. Pat. No. 6,071,224 discloses a copy-carrying cylinder having guides for extensible folding elements. The copy-carrying cylinder provided in a copy-processing machine includes two opposing and cooperating cylinders receiving copies on their peripheral surfaces. The copies which are retained on the peripheral surface of one of the cylinders are conveyed by an extensible folding device into receiving elements at the peripheral surface of the other cylinder. At the peripheral surface of one of the cylinders, provision is made for covers bounding an opening through which a folding device, which is accommodated in a hollow space in the interior of the cylinder, moves in and out.
The design approaches known from the related art indeed limit the opening at the peripheral surface of a copy-carrying cylinder in the region of a folding device which move in and out but can be accessed only with considerable effort from the lateral surface of the folding cylinders which are difficult to access anyway, for example, for replacing a worn out folding device such as sets of impaling pins or folding blades.
In view of the indicated related art, an object of the present invention is, on one hand, to maintain an as continuous as possible peripheral surface on copy-carrying cylinders and, on the other hand, to provide an easy way to access folding devices which are supported in the interior of the cylinder.
The present invention provides a copy-carrying cylinder having a peripheral surface (2) for carrying sheet-like copies which can be acted upon by a folding device (5) which is used for producing a fold and which can be moved out of an opening (4) in the cylinder (1). A movable surface element (13) is associated with opening (4), wherein the surface element (13, 13.3) is designed and arranged near the folding device (5) in such a manner that, via the application of a pressure force, it can be moved into an open position in which it enables access to the folding device (5), and that it automatically moves from the open position into a closed position subsequent to canceling the pressure force.
The advantages which can be attained using the design approach according to the present invention are to be seen above all in that it allows the clearance next to a retractable and extensible folding device at the peripheral surface of copy-carrying cylinders to be closed so that a virtually continuous lateral cylinder surface ensues. Corners are prevented from being turned down during the transfer of the sheet-like copies from the peripheral surface of a copy-carrying cylinder to the peripheral surface of another copy-carrying cylinder cooperating therewith. Besides, the arrangement of a pivoted surface element proposed according to the present invention offers the possibility of easy access to the fastening elements for a folding device in a hollow space provided underneath the lateral surface of a copy-carrying cylinder. The closing of the pivoted surface element is assisted by the centrifugal force acting upon the hinged surface element during the operation of the copy-carrying cylinder. The surface element can be swiveled open in an easy and simple manner using a tool, for example, a wrench so that there is immediate access to fastening elements for a folding device such as impaling pin bearing arrangements or folding blades or the like.
In an advantageous embodiment of the basic idea of the present invention, the surface element can have a one-part or also a multipart design. If the hinged surface element is designed in one piece, it acts as a guide surface for tools to be introduced into the hollow space underneath the peripheral surface of the copy-carrying cylinder; if the surface element has a multipart design, a hinged segment of the surface element can be adapted in optimum manner to the tool to be introduced into the hollow space underneath the peripheral surface.
The surface element can be advantageously accommodated on a wall bounding the opening in the peripheral surface of the cylinder. The cylinder can be provided, for example, with a hinge bearing which supports the surface element more or less centrically and which allows the hinged surface element to deflect from a closed position (operation) into an open position (maintenance work).
At the hinge bearing, the surface element can be moved about a swivel pin which can have a spring element associated therewith.
In a first variant of an embodiment, the spring element can be designed as a spiral spring which surrounds the swivel pin and whose free legs, on one side, are braced against the lower side of the surface element which is deflectable about the swivel pin and, on the other side, are braced against a wall which bounds the hollow space underneath the lateral cylinder surface. Besides, it is possible for the spring element to be designed as a pressure spring which can be articulated both to the hinge bearing of the surface element and to the lower side of the surface element.
In the one-part embodiment of the hinged surface element, the hinged surface element can be provided with a contact surface over the opening for the retractable and extensible folding device, the contact surface plunging into a recess provided at the peripheral surface of the copy-carrying cylinder, when in the closed position. In this variant of an embodiment, the surface element, when in its closed position (operation), forms a virtually continuous surface with the adjacent region of the lateral cylinder surface.
In another variant of an embodiment of the surface element proposed according to the present invention, it is possible for the surface element to have a multipart design, i.e., provision is made for a hinged segment and a stationary segment of a surface element. The hinged segment of the surface element can be put against the wall of the hollow space underneath the lateral cylinder surface in a spring-loaded manner by introducing a tool, while the stationary segment remains in its position. According to this variant of an embodiment, the size of the hinged segment of the surface element can advantageously be adapted to the maximum size of a tool to be introduced into the hollow space underneath the lateral cylinder surface.
Using the design approach proposed according to the present invention, the accessibility of fastening elements in hollow spaces of cylinders as, for example, copy-carrying cylinders in folding apparatuses or rotary printing presses is considerably simplified. A removal of the cylinders for maintenance work can be avoided, permitting a drastic reduction of down times of folding apparatuses and rotary printing presses cooperating therewith for carrying out maintenance work. Via the action of centrifugal force during the rotation of the cylinders, it is ensured that the pivoted surface elements or segments of the surface elements always take their closed position while the copy-carrying cylinders are in operation, resulting in a virtually continuous peripheral surface of the copy-carrying cylinders designed according to the present invention during the operation thereof.